Have you had your coffee yet today? Do you feel that caffeine is helpful, perhaps even necessary, to being alert and energetic? You may want to reconsider regular use of caffeine.

Caffeine is one of the most, if not the most, commonly consumed drugs among humans. A 2005 extensive survey found that 87% of Americans consume caffeine regularly, with an average intake of 193 mg per day.

The most common sources of caffeine are coffee (71%), soft drinks (16%), and tea (12%). Other sources include chocolate, over-the-counter medications (like headache or cold medications), and dietary supplements. Caffeine derives from the coffee bean, cocoa bean, kola bean, and the guarana fruit.

While many people feel that caffeine is a performance enhancing substance, the evidence has been largely against this notion, if somewhat mixed. But a recent large study strongly supports the evidence against any true cognitive or alertness benefit for caffeine.

The study authors looked at 162 non/low caffeine users and 217 medium/high caffeine users. They were also interested in the effects of specific genetic variants, ADORA2A and ADORA1 polymorphism, that render people more sensitive to certain caffeine effects. They had participants refrain from caffeine use then challenged them with increasing doses of caffeine or placebo, and assessed their anxiety, alertness and headaches.

They found that caffeine withdrawal (giving placebo to high caffeine users) caused increased headaches and decreased alertness. This is no surprise and supports prior research. In my own practice I see a great deal of caffeine withdrawal headaches and can sometimes “cure” patients just by having them stop their daily caffeine use.

When regular caffeine users were given caffeine this simply returned them to their baseline, and did not enhance their alertness. Non caffeine users saw no benefit from taking caffeine.

Caffeine also caused anxiety in non caffeine users, especially those with certain genetic variants. However, it did not increase anxiety in regular users, who therefore seem to be tolerant to the anxiety-producing effects of caffeine – even if they had the susceptible gene variants.

The take home is that regular use of caffeine produces no benefit to alertness, energy, or function. Regular caffeine users are simply staving off caffeine withdrawal with every dose – using caffeine just to return them to their baseline. This makes caffeine a net negative for alertness, or neutral at best if use is regular enough to avoid any withdrawal.

Meanwhile, regular caffeine use (even without withdrawal) can increase blood pressure, worsen headaches, cause palpitations, insomnia, and jitteriness. Intermittent use can also increase anxiety, although this study showed regular users become tolerant to this effect.

I am not trying to be down on caffeine, just report the research. This research also shows that caffeine is generally safe, and while it does increase blood pressure (a risk factor for heart disease) caffeine is not an independent risk factor for heart disease itself. There is also evidence that regular caffeine use (perhaps just coffee use) decreases the risk of Type 2 diabetes. Pregnant women should avoid caffeine because of potential effects on fetal growth and spontaneous abortion. Migraneurs should also avoid caffeine as it can worsen a migraine syndrome.

But if you do not have any specific medical condition that caffeine can exacerbate, regular moderate caffeine use appears to be safe. Just don’t fool yourself into thinking it is helping you stay alert or function better.

54 Responses to “Caffeine”

In all seriousness I knew (more or less) that I might as well drink placebo (not being a major user). I had tested myself inadvertently when I forgot to out the teabag in the tea, and thus drank hot sugar water and received the ‘placebo perk’.

Will I give up caffeine entirely based on this evidence?
Probably not.

Its in too many delicious things like Tea, Chocolate, Coffee, etc.

But, I will no longer seek it out as I once did (many years ago), and will try to remember its effects as I try to shake off my morning grogginess.

It’s good to see a well-designed study on caffeine. However, it doesn’t look like this study addresses the main use case for caffeine: as a stimulant to combat sleep deprivation. I don’t have full access to the article, but it looks like they only tested habitual use. Did they also control for well-restedness?

My understanding about the mechanism of caffeine is that it is an adenosine antagonist, which can allay the effects of sleep deprivation temporarily. This is why people start using it, and why they fall into the trap of habitual caffeine use. Caffeine may have no benefit in alertness to well-rested individuals, but what about in sleep-deprived users? An additional pair of sleep-deprived caffeine users and sleep-deprived non-users would have been more informative, I think.

There are many effects of caffeine this study did not cover, and therefore I did not delve into. It is a complex molecule, biochemically.

I found it interesting that caffeine is an adenosine A1 antagonist, when the “acupuncture” study found that adenosine A1 agonists relieve pain. So does caffeine exacerbate chronic or acute pain? Or will caffeine block the temporary beneficial effects of local manipulation?

I love the taste of coffee and I drink it black. I have one cub every morning, and yeah, if I don’t have that cup I can get a headache, which is easily remedied by a cup. Ultimately, it’s part of my morning routine at work and if there’s no real damage to one coffee daily, I’d rather not give up the deliciousness that is coffee. 🙂

Migraneurs should also avoid caffeine as it can worsen a migraine syndrome.

Mileage varies — caffeine actually seems to help some migraine sufferers. My mother is one of them. She gets really nasty migraines, the kind where you’d gladly drill a hole in your own head if you thought it would help, because nothing could be worse than the migraine itself. I’ve also known migraine sufferers who get some relief from alcohol, and those who get much worse migraines with alcohol. (My godmother won’t touch booze at all because it triggers migraines for her.)

But a migraine is so painful that trying caffeine would be kind of like Russian Roulette.

This caffeine research confirms what was the evidence was already pointing to regarding caffeine use and alertness. The main effect of caffeine on alertness is reversal of withdrawal. The lack of positive effect on alertness in noncaffeine users is a bit surprising. I think other research has demonstrated otherwise.

Coffee has been associated with a lower risk of more than just diabetes. There are also associations for lower risk of dementia, stroke, among others. Of course these are not clear cause and effect, but most of the studies incolving coffee have been positive or neutral. Lets not assume that coffee and caffeine are one and the same (with the exception of its effect on alertness). Also, many people drink coffee because they enjoy it, not for any perceived health benefits or just as a drug to increase alertness.

I enjoy coffee from time to time, but don’t drink it regularly since I noticed that I am get more headaches when I do.

I’m aware of the lack of an alertness effect of caffeine (I think I learned it from Steve on an SGU episode.) Still, I’ll grab a cup on my way to a meeting, knowing I might need something to keep my eyelids from getting too heavy. I think it’s an oral fixation/activity that helps me from getting sleepy. When I drive, I keep a bag of sunflower seeds nearby – a cheekful of seeds (which I have to crack, remove the seed, spit out the shell) works *far* better than anything else I’ve tried at keeping me awake.

I’d like to see a study that tests such activities for alertness, wakefulness, etc.

I certainly does, but over time it can worsen things. The more frequently caffeine is used for migraines, more likely they are to get rebound headaches from its use. It can end up a viscious cycle as the person habituates to the effect of caffeine, and they end up “treating” caffeine induced headaches.

Ok, Steve, you got me. I did not fire up the Mr. Coffee today. But what now?

What do we know about the deterioration of caffeine tolerance? For how long would we expect caffeine addicts to be “below baseline” after quitting? Is there some sort of half-life for the decay of caffeine dependency or has my intermittent use doomed me to permanent sub-par attentiveness?

I have been counseled by physicians, a gynecologist and a cancer specialist to decrease or avoid caffeine consumption because of the increased risk of breast cysts/ or potentially cancerous cysts. The gynecologist recommended the use of 800 I.U. to decrease the inflammatory effects of caffeine on the body. A pharmacist recommended d-Alpha Tocopherol as the best based on spectral tests.

Never drank coffee till I was in my 60’s. Always felt lethargic, had trouble concentrating and remembering a phone number long enough to dial it. Also suffer from RLS.
Started drinking one cup instant in the morning when I couldn’t get my usual hot cocoa and noticed improvement in RLS and memory along with more energy and focus. Get a lot more done now.
Anecdotal I know … but I will continue the experiment.

Also interesting that the Enlightenment seemed to follow the development of coffee houses in Europe.

Hi, Steve!
What do you think of using caffeine as a thermogenic?
Here is a link from the American Journal of Clinical Nutrition:http://www.ajcn.org/cgi/content/abstract/49/1/44
But this research is more than 20 years old.
What is your opinion on this?
Thanks!

I am patiently awaiting my old baseline. I have drank copious amounts of coffee for the last 6 or 7 years. Not that long ago, I started crashing, hard about midway through the day (I have never sugared my coffee, only black) It made me feel terrible, shake, perspire and feel ill. I decided to give it up. It’s been a couple of weeks now and I will occasionally have a cup or two of decaf (of course, understanding that there is still some caffeine in decaf, just much less) It’s been rough, to say the least. I am dragging to get through the days. I haven’t had any shaking or other typical withdraw symptoms really, but I do feel very tired, regardless of how much rest I get. Coffee will be one vise I won’t miss once I get over this hump. The whole smoking thing is next on my list. Does anyone know of any research into possible synergistic effects of smoking and drinking coffee?

If find that hard to believe. I went without caffeine for 3 years. When I started again, I had a marvelous energized feeling for about an hour. I only got that effect the first few times. Now I use to avoid withdrawal, because I feel so tired and cranky when I need the ‘fix’.

I want to go off slowly to avoid the withdrawal. Does anyone have a suggestion of the best withdrawal step down?

Wrote off the advice on Caffeine for migraine sufferers when I first heard it from you on SGU, on the basis of caffeinated pops being delicious and tracking down the non-caff versions a pain, but a couple months ago I had a really bad 2 weeks for my migraines and dropped the caffeine. Back to having them very rarely and now a bit of caffeine actually has a stimulant effect on me (shown by the night I popped some Excedrin Migraine on my way out the door at around 8pm since my head was starting to be a bit of a pain, and realized at 3am why I was still up when I had nothing I needed to be doing that late).

“Does anyone know of any research into possible synergistic effects of smoking and drinking coffee?”

One important thing to consider is the possible trigger effect of drinking coffee on desire to smoke. It depends on the person and their habits, but some people who often drink coffee while smoking find that a cup of coffee can be a strong trigger for a desire to smoke. Its important to identify your triggers when trying to quite smoking, and I would recommend participating in a smoking cessation program for a comprehensive approach.

I do indulge in that from time to time. I find caffeine free coffee to be a very good substitute for the most part. Decaf tea, on the other hand, is universally terrible (and I’ve tried every brand around) regardless of their method of caffeine removal. Luckily caffeinated tea doesnt affect me in the same way, and I drink that most often (PG tips brand or any assam)

As someone who had issues with caffeine (tea and coffee), I’ve long given it up, I also am surprised at the low effect quoted for non-users, as I’ll occasionally look at the clock at 03:00AM and realize I’ve accidentally drunk caffeinated beverage that evening. Possibly the protocol just doesn’t measure the effect on sleep onset, which I think is well established.

The issue I pick up on in the literature was osteoporosis, possibly because I was looking from the perspective of a hyperthyroid person and seeing what symptoms overlapped, but I think this is the same for many stimulants that they can reduce bone density over the long term – probably only matters if you have a bone density problem to start with.

“On the other hand, decaffeinated instant coffee is the pits. There’s no substitute for freshly ground coffee beans.”

I definitely agree with the second statement… I think most people who have had it would agree. The problem with instant coffee (up until very recently) is the U.S. market. Instant coffee is largely viewed in the US as a very low end product purchased by people who don’t care much about taste or don’t drink coffee. So they make low end product. It seems as this is changing a bit, with some more premium instant brands popping up. I noticed in Japan they have a lot of fairly pricey (by US standards) instant coffee products, which taste nearly as good as some drip coffee (but still nothing like fresh ground or high quality coffee)

“I also am surprised at the low effect quoted for non-users, as I’ll occasionally look at the clock at 03:00AM and realize I’ve accidentally drunk caffeinated beverage that evening.”

They never said there was no effect of caffeine on non-users, just no positive effect on alertness. There was still an increase in anxiety, which could prevent you from sleeping well. I just avoid heavily caffeinate beverages in general, and particularly towards the second half of the day.

It matches my personal experience. I used to drink 6-7 espresso a day. I went cold-turkey for about 2 months, initially suffering the massive headaches and lethargy. But now I drink one a day, and my level of concentration at work is the same as when I was drinking so much coffee, but now I don’t get the nasty withdrawal symptoms…

“What is the evidence that pregnant women should avoid caffeine? Is there any wiggle room for moderation?”

The results are mixed. Most of the decent studies point to no risk to a very small risk. Caffeine does not appear to cause birth defects, and this has been studied. There are a couple of studies that suggest a small increase in miscarriages at high levels of caffeine consumption, but other studies don’t detect such a risk. Doing studies like these are problematic since people who drink large amounts of coffee during pregnancy are likely very different in other ways. You can attempt to control for these differences, but there will be some problems with doing this.

The current recommendations vary from keeping under 150 to 300mg of caffeine per day, and it depends on the study from which they base their recommendations from. I would limit the consumption of coffee/caffeine to the extent that you feel comfortable after feeling well informed.

Also the caffeine and osteoporosis thing isn’t straight forward. Some studies (I think mostly in asia) show that tea drinking is associated with an increased bone mineral density, although I dont think this has panned out in terms of fracture risk. Of course this probably has nothing to do with the caffeine itself, but if the effect were clear cut the opposite would be expected.

Has anyone else besides me noticed the puritanical streak in some of this research? If it’s fun it must be bad for you. Caffeine, alcohol, chocolate, can sex be far behind? Particularly for pregnant women, who are supposed (I guess) to be more virtuous than the rest of us.

So far as I can tell the studies on pregnancy and caffeine are, as we phrase it, “mixed,” which means we’re not a lot wiser after doing the studies than we were before. This seems a slender thread upon which to hang a prohibition. (Of course someone who was concerning with being perfectly safe wouldn’t get pregnant in the first place, since pregnancy itself carries some very small risks to health and sometimes life. Not to mention what happens to you after the baby is born!)

Sometimes I think we need to lighten up. We’re all going to die of something sooner or later, and apparently no one is going to die of coffee. At least not very many people.

When I can the jitters from caffeine (after having a coffee or two, which isn’t something I commonly do) its usually because I’m awake when I wouldn’t have been otherwise.

Anyways I wouldn’t be surprised if my daily tea ritual was pleasing mostly because tea tastes good and the hot water is soothing. I guess I don’t notice much difference between green and black tea, although black tea has twice as much.

So a quick search through pubmed seems to show that almost every study that looked at caffeine’s affect on alertness found the opposite of this study. Why would that be?
Also, since my school doesn’t have access to Neuropsychopharmacology, does anyone know how they measured alertness?

Decaf tea, on the other hand, is universally terrible (and I’ve tried every brand around) regardless of their method of caffeine removal.

Have you tried decaffeinating it yourself? I learned this trick, and while I’m not sure how effective it is, it’s encouraged me to get a lot more out of my tea.

According to the lady on TV (citation not available, warning, warning!), nearly all of the caffeine (she claimed 90%) leaves the tea leaves in the first thirty seconds of steeping. Yet it is usually recommended to steep the leaves for two to five minutes, depending on personal preferences. So the solution she had was to dip the teabag or infuser in a cup full of hot water for thirty seconds, pull it out, dump the tea, refill with more hot water, and finish steeping. I’ve been doing this for some time, and have found I get an entirely acceptable cup of tea. I’ve also done it at the pot scale; I fill a pot with hot water and a mug with hot water, put the infuser in the mug, wait thirty seconds, transfer it to the pot, and brew myself a pot of decaf tea.

I am also known to hang on to teabags and use them three or four times; the third and fourth steeping tend to be rather weak and sometimes they get a bit vile; I suspect the problems with decaf tea are related to this, where the longer used tea sits out, the worse it gets.

All good points. However you lack to mention a few things. One the direct effect…
“Aside from a medical view, positive and negative aspects aside, it remains the best contender fighting sleepiness with it’s clear ability to murder sleep. Caffeine directly interferes with our the bodies adenosine receptors. These are our “natural” sleeping pills. Caffeine falls into the xanthine chemical group, including adenosine. To our nerve cells, caffeine looks a lot like adenosine, in turn it binds to our receptors in the basal forebrain. When consuming caffeine the brain cannot determine the difference between adenosine because the caffeine is taking up the receptors causing the cells to speed up hence giving us energy and an awakening effect. In a sense, coffee tricks our brains into releasing adrenaline naturally. However there is still the underlying question that remains if it is actually unhealthy or not. Like any other mind and body altering chemical precautions and education need be applied. In moderation caffeine shows very few negative effects. If you’re the person drinking 10 cups a day then of course you’re going to have complications because you’re going against the natural process of the body. Take wine for instance, a glass a day, great, a bottle probably not. If you abuse your body there will be negative consequences.”

“But a recent large study strongly supports the evidence against *any true cognitive* or alertness benefit for caffeine.
[…]
The take home is that regular use of caffeine produces no benefit to alertness, *energy*, or *function*.
[…]
Just don’t fool yourself into thinking it is helping you stay alert or *function better*.”

(Emphasis mine)

Now, I read the referenced study before having coffee, but apparently, it only measured alertness (and anxiety and headache), not these other things you mention.

I am disappointed that this article not particularly balanced, and reading between the lines, could be considered border-line scaremongering. Lots of negatives discussed in your article, and very few (if any) positives.

It is a shame that you didn’t mention that caffeine (when combined with complementary substances) can aid in weight loss by liberating triglyceride (fat) stores during exercise. As an ergogenic aid (for exercise) caffeine can improve the efficiency and efficacy of energy systems, resulting in longer exercise, lower fatigue and higher overall energy consumption. Again, on the issue of weight management – which is a bigger concern in the US than the side-effects of caffeine consumption – caffeine’s effect on the brain can contribute to longer periods of satiety.

And what about the cardio- and neuro-protective potential of caffeine for healthy subjects?

Yes, Caffeine does have some noticeable side-effects in humans, but they are nothing in comparison with the those associated with smoking, alcohol consumption or a deluxe cheeseburger from your local brand fast-food outlet.

Like # brettwelsch mentions – in moderation!

For an MD compiling this blog, I am surprised at the obvious one-sidedness of this article.